MS Community Manager Graeme 'AceyBongo' Boyd has just what the pricing will be for the new 250 GB HDD in the UK:
"Ugh. I got the UK pricing for the 250GB hard drive wrong too. It's ERP £79.99, not £64.99 as I said yesterday. Really sorry... (*gives up*)"
The new hard drive will be out on April 16th, and will come with a Data transfer kit for content migration.